I have heard that non R/C engines such as the ones used in chainsaws ... for tree cutting and weed trimmers are useable in aircrafts with a slight modification.

I am being sold a Robin 50 CC engine ... it comes with the mechanical crop sprayer thing....will it work ?

What sort of eninge is really useful for such purpose ?
Do they really work ?
What size is good ? (the sizes available to me are 30 cc ----- 70 cc)

they are really really cheap here and i want to build a big sports plane for it.

Waiting for your generous help !
USMAN.

is that a 4 or 2 stroke? if it is a 4 it is probably too heavy for practicle RC use. (robin/subaru makes some 4 strokes in that range)

Its was a 2 stroke

besides there are many many engines available in that range.

Many engines can converted to Rc airplane engine, I have some. Poulan 46 is ideal, it is almost ready engine, just make a prop hub and go to fly, with a bit of work you can converted a Homelite 25 cc mine turns a 18x10 APC 8500 rpm. take a look to:
http://www.shark-racing.com/Ingles/T...acaoMoting.htm